The Nvidia driver does not "work" in my project. I have added no code which explicitly blacklists it, and the day Nvidia releases a driver which implements the required APIs it will work with no changes in my code.
How about the day when Nvidia releases a buggy (system-crashing?) implementation of the required APIs? How well will your code work without changes, and which course of action will you take?
Chromium chooses to prioritize users' experience over scoring ideological points. That means attempting to work around known external bugs instead of letting things blow up and sending users to pound sand on some unresponsive third-party mailing list.
I'm not sure how you can fault them for that, especially since pretty much all successful large-scale projects take the same approach -- including the Linux kernel.